Actuator Command Filtering for Safe External Process Control
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Solution Overview
Problem
In process engineering plants, improper use of external control consoles, including unauthorized access, can lead to safety-critical conditions and damage by triggering field device control commands, resulting in undesired downtimes and potential harm to the plant.
Innovation Solution
A communication device with an electronic permissibility checker is implemented to ensure only permissible actuator commands are transmitted to actuators, using a data memory to store predefined safe commands and prevent unauthorized or unsafe control, thereby acting as a safety barrier to exclude improper operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If external control console is used for process control, then ease of operation is improved, but safety and reliability deteriorate due to unauthorized access and improper use
Solution Approach 1:
The patent introduces a communication device as an intermediary between the external control console and the actuator. This mediator filters control commands, allowing only predetermined permissible commands to reach the actuator while blocking unauthorized or unsafe commands. The device stores a list of permissible actuator commands and compares incoming commands against this list, thus enabling easy operation through the external console while maintaining safety through automated command validation.
2Reliability
If access control restrictions are implemented, then safety is improved, but ease of operation worsens due to limited access
Solution Approach 1:
The patent implements preliminary action by pre-defining and storing a list of permissible actuator commands in the communication device before operation begins. These permissible commands are predetermined based on safety requirements and operational needs. During operation, the device automatically checks incoming commands against this pre-established list, enabling safe operation without requiring real-time authorization decisions, thus maintaining ease of operation while ensuring safety.
Data Source
AI summary
A communication device for control interaction between operating electronics and an actuator to set a process fluid flow of a process-engineering plant can include a first communication interface configured to receive electrical signals from the operating electronics, a second communication interface configured to provide electrical actuator commands to the actuator, and a permissibility processor having a data memory that stores permissible actuator commands, the permissibility processor being configured to cause the second communication interface to provide one of the permissible actuator commands to the actuator based on an electrical signal of the electrical signals received via the first communication interface.